SACRAMENTO, Calif. -- One day after ordering a four-month halt to imports of modified assault weapons, President Clinton ridiculed yesterday the notion that such firearms could be used for anything but making mayhem.

"You don't need an Uzi to go deer hunting, and everyone knows it," the president said in his weekly radio address. "Assault weapons in the hands of civilians exist for no reason but to inspire fear and wreak deadly havoc on our streets."

Friday, Clinton halted for 120 days the importation of such firearms, blocking permits already issued to dealers for 600,000 guns and freezing applications to import a million more.

During the four-month period, the Treasury Department will consider banning the guns permanently. The Treasury Department has the authority under the 1968 Gun Control Act to ban imports of such firearms if they are not used for "sporting purposes."

The National Rifle Association yesterday attacked Clinton's announcement and released a statement saying that the president is attempting to extend a 1994 ban on assault weapons to a whole new class of weapons.

"Everything the NRA has ever said about the Clinton 1994 gun ban is coming true," the organization said.

In remarks Friday night, Clinton boasted of the 1994 assault weapons ban, which applied to the domestic manufacture, sale and possession of 19 types of assault weapons, and banned the domestic manufacture and sale of semiautomatic weapons with certain military characteristics.

In his weekly radio address, which he taped Friday before leaving Washington for a weekend of speeches and fund raising, Clinton said that the weapons he seeks to block are virtually indistinguishable from ones that are already banned.

He accused "some foreign gun manufacturers" of attempting to evade the restrictions by "making minor modifications to their weapons that amount to nothing more than cosmetic surgery."

Clinton disclosed his move against firearms imports late Friday night, at an event to raise money from Democratic women in Las Vegas. At the end of a list of administration positions that have wide support among women, Clinton described the ban and then used harsh language in asserting his determination to make it stick.

"I am not going to let people overseas turn our streets into battle zones," the president said, "where gangs are armed like they were guerrilla warriors halfway around the world, if I can stop it."

In his directive Friday to Treasury Secretary Robert Rubin to suspend imports, Clinton said, "The number of such firearms for which import applications have been filed has skyrocketed."